Physicians frequently insert hollow hypodermic needles into vessels near the surface of the body of a human patient to introduce fluids, draw blood, insert catheters, and perform other diagnostic and therapeutic activities. The present invention provides apparatus for isolating or locating an artery or vein near the surface of the human body and assists the clinician in inserting hypodermic needles at the proper location. The present invention therefore shortens the time required for proper needle insertion, reducing the cost of medical case and minimizing patient discomfort.
This application is related to the subject matter of application Ser. No. 07/500,710, filed Mar. 28, 1990, entitled Ultrasonic Guided Needle, hereby incorporated by reference, which relates to locating a hypodermic needle into arteries or veins deep within tissue. That application describes apparatus which transmits a sonic beam through the hollow metal needle of a standard hypodermic needle. When locating vessels deep with a body using the apparatus described in Ser. No. 07/500,710, the needle typically must be aspirated and located below the skin before the angulating the needle to locate the vessel. Surface vessels cannot be isolated in this manner, since the searching operation must be performed prior to piercing the skin.